What is the annual sales figure for mattresses in the US?

This question may seem difficult if you're unprepared for it. Nonetheless, it is categorized as a market-sizing or estimation question commonly posed by consulting firms to evaluate your analytical and problem-solving abilities. The interviewer does not expect an exact number; instead, they are interested in your methodology and logical reasoning in tackling the problem. It is crucial to verbalize your thoughts so the interviewer can follow your reasoning. Start by considering the number of households in the US, the average lifespan of a mattress, and how often households typically replace their mattresses.

To begin, I would calculate the number of households in the United States. With a population of roughly 330 million and an average household size of 2.5, there are about 132 million households. If we assume that each household has an average of 2 mattresses and that a mattress typically lasts for 10 years, households would be replacing their mattresses every decade. Therefore, by dividing the 2 mattresses per household over a 10-year period, I would estimate that around 26.4 million mattresses are sold each year in the US.

Let's examine the US population, which is roughly 330 million. If we take into account that an average household has 2-3 individuals, this results in approximately 132 million households. It’s reasonable to estimate that each household possesses about 2 mattresses. Considering that mattresses typically last between 7 to 10 years before they need to be replaced, we can estimate an average lifespan of about 8.5 years. Therefore, in terms of replacements alone, we can expect around 31.2 million mattresses sold each year. Additionally, we must factor in mattress sales due to reasons other than replacements, such as the construction of new homes. Taking into account the growth rate of the US housing market, let's add an extra 10% for these cases. Consequently, my estimate, based on these calculations, would be approximately 34.32 million mattresses sold per year in the US.